If the moon had precious metals on it we would mine it today already, that much is certain.
There's at least a factor of 40 between the spot price of gold and the round-trip cost per kilo of materials on the moon. You're welcome to play around with numbers to see how you could make that profitable. However, whether the gold was in lunar orbit, at the bottom of the Marianas Trench, or in the Oort Cloud the same principle would still apply: value is a social and subjective construct which cannot be said to be intrinsic or inherent to anything. If we aren't mining something, it is actually valueless.
However taken all by itself, out of context of that group, desired by a subset of people this number has no value that is worth anything to anybody.
You recognize that the coin has value when in the network, and none without the network. I wonder what the difference could be? Look, this is a clumsy rationalization. You don't like the idea of these currencies; neither do I. Your thought process is to highlight the differences between CCs and real currencies, and then look for reasons why that means that CCs are bad. You have an agenda, then you go looking for facts. In other words, you're a tool.
Currencies actually work better when they have no intrinsic value. It's one of the reasons that commodity money is rarely found outside black markets: you don't really want your cash to be a consumable. Gold and silver were used as coinage because they were scarce and durable, and in spite of the fact that they could be worked.
Your premise is flawed and your argument is invalid. That cryptocurrencies do not currently fulfill all the functions of money happens to be true, but BitCoin is becoming more stable and widely adopted all the time. There is no real difference between it and any other currency other than the issuer and the current volatility. Your homework is to read about the functions of money.